This disclosure relates to a cooling system for a computer system having multiple chip modules and in particular to a cooling system having a first and second cooling loop that share a common condenser and have a controller that adapts the operation of the cooling system to maximize efficiency and reliability.
The use of complementary metal-oxide-semiconductor (“CMOS”) based microprocessors has allowed large advances in the construction and operation of computer systems. CMOS semiconductors dissipate less power than prior art semiconductors such as bipolar circuits. The use of CMOS semiconductors therefore allows denser packaging and faster circuits. These advances are further aided by the characteristics of CMOS semiconductors that allows faster operating speeds when the microprocessor is cooled and thermal energy is removed during operation.
Recently, the use of multiple chip modules (MCM) in computer systems has allowed additional increases in speed and processing power. However, these MCM systems also generate significant amounts of heat. Since there is a demand to run the MCM systems at higher speeds, the clock frequencies of these devices must be correspondingly higher. Unfortunately, the thermal energy generated by an MCM system rises in proportion to the microprocessor clock speed. Thus, the demand for higher clock speeds requires maintaining the microprocessor at consistent low temperature that places strains on the cooling systems of these MCM systems. These issues are further compounded by the desire for the cooling systems to be efficient and highly reliable.
Typically, a cooling system for this type of computer system was arranged to support multiple MCM systems. This arrangement typically included a single reciprocating compressor coupled to a condenser. Multiple cooling loops were manifolded to the outlet of the condenser allowing the cooling of the individual MCM systems. Each of the cooling loops are manifolded back together at the inlet to the compressor. While this system met the desired cooling requirements, the compressor is often under utilized since it is designed to meet maximum heat load requirements for each supported MCM system. By operating the cooling system at levels significantly less than the designed performance levels, the efficiency and reliability of the cooling system decreases.
While existing computer cooling systems are adequate for their intended purposes, it is desirable to have a computer system that can be cooled by a compact and reliable cooling system having separate cooling loops to provide increased reliability and efficiency. It is further desirable for the cooling system to be arranged in a manner that allows adjustment of the operation of the cooling loops to compensate for higher heat loads in one of the MCM's. In addition, it is desirable for the cooling system to be arranged so that the individual cooling loops provide a redundancy in the event of a failure in one cooling loop.